In many applications directed or related for example to dispensing of liquids, such as dispensing of deodorizing agents into the atmosphere, application of disinfectant or cleaning solutions to a surface, application of pesticides or fertilizers or the like to agricultural product to name only a few, it is desirable that a liquid agent, or particulate agent suspended in liquid, be dispensed as small droplets in a spray form.
Currently it is convenient and typical to store a liquid agent in a pressurized reservoir in its liquid form and then to expel the liquid from the reservoir with the aid of a propellant gas so that the liquid is dispersed into the surrounding atmosphere. Alternatively, liquid particles may be entrained within a pressurized gas stream prior to leaving the reservoir outlet, or allowed to evaporate in a lower pressure region outside the reservoir in order to achieve a spray-like dispersion.
The sprayed dispersion of the liquid in such manners can be difficult to accurately control. For example, there may be a difficulty in controlling the volume of liquid in part due to non-uniformity of the flows of gas and/or liquid leaving the reservoir. This is undesirable in applications where a measured dose of the agent is required, or where the agent needs to be applied at a particular rate.
Additionally, there may be variability in the size of droplets in such a spray. Those droplets which are too large or heavy may not be effectively and uniformly dispersed into the surrounding environment, resulting in areas of excessively high concentration of the agent proximate to the spray outlet and/or areas of insufficiently low concentration farther from the spray outlet. In the example of pesticide application, areas of high concentration may result in plant toxicity due to over-application. In the example of disinfectant application, the areas of low concentration may result in insufficient sterilization, or over-application in areas resulting from attempts to avoid or mitigate such areas of low concentration.
It is therefore an object of the present invention to provide a apparatus for dispensing a liquid drawn from a reservoir as an atomized spray which addresses or overcomes such disadvantages.